Telemetric system



Nov. 19, 1946. s, PETERSON 2,411,389

TELEMETRIG SYSTEM Filed Sept. 11, 1945 5 sheets-sheet 1 REMOTE AZIMUTH INDIOATING STATION 7 Egg INVENTOR.

w EDWARD s. PETERSON u-I 8? L1.

ATTOR NEYS 1946. E. s. PETERSON TELEMETR IC SYSTEM Filed Sept. 11, 1945 3 Sheets-Sheet 2 INVENTOR. EDWARD S. PETERSON ATTORNEYS NOV. 19, 1946 s, PETERSON 2,411,389

TELEMETRIC SYSTEM Filed Sept. 11, 1943 3 Sheets-Sheet 3 FIG. 4

INVENTOR. EDWARD S. PETERSON ATTORNEYS Patented Nov. 19, 1946 UNITED STATES PATENT OFFICE TELEMETRIC SYSTEM Edward S. Peterson, Elmwood Park, 111., assignor to Automatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application September 11, 1943, Serial No. 501,956

1. Claim. 1.

This invention relates. to telemetric systems and, more particularly, to a system of this type especially adapted for theremcte indication of azimuth of a direction finder.

To locate a radio transmitter, a plurality of observation points is established, each using a direction finder, and the azimuth observed at each direction finder is transmitted to a central point where, by triangulation, the radio transmitter is located. To facilitate this transmission of observed; azimuth from a plurality of direction finders to a. central point each direction finder is provided with a telemetricsystem. to indicate continuously at the central point the azimuth obtained by. the individual direction finder. When portabledirectionfinders are used it of course is desirable to provide remote azimuth indication with the simplest type of telemetric systemv which will operate with the. desired degree'of accuracy. It furthermore is desirable to obviate the necessity of using a power sourcewhichrequires careful control or regulation of either frequency orvoltage as would be. the case. were alternating power to be used. Insetting up portable direcarrangement whereby a reference point on the azimuth scale of the direction finder may be coordinated' with a corresponding reference point on the scale of the remote.- azimuth indicating apparatus. When the referencepoints have been coordinated all subsequent indications at" the remote point will correspond accurately with the azimuth indications at the direction finder.

Itis therefore an object of this invention to provide an improved telemetric system for reproducing at a remoteipoint the angular displacement of a member in either'direction.

Another object of this invention is to provide an improved telemetric system for reproducing angular displacement of amember with the control means for coordinating a predetermined reference point on an angularly displaceable member with a reference point on a remote indicating member.

Still another object of this invention is to provide an improved telemetric receiving apparatus for indicatingthe angular displacement of a re-' motely positioned member.

'Still another object of the present invention is to provide an improved tel'emetric receiving indicator with means for' coordinating the indicator'with a reference point on a-remotely located angularly displaceablemember;

In accordance. with the present invention, each of a plurality of direction finders is provided with an azimuth scale for observing the azimuth. of. a. radio transmitter, the location of which is to be: obtained by triangulation. Each direction finder is connected by a telemetric; system to the centralpoint. This telemetric system includes an im pulse transmitter at the direction finderwhijch transmits over a plurality of channelsa predetermined number of impulses: corresponding. to.

, the; angular displacement of the azimuth scale.

At; the remote azimuth indicating station these impulses are received and translated into a cor responding angular displacement. of an azimuth indicating scale. At the. time. when portable direction. finders are set up for operation. it, of course, is necessary to correlate the azimuth. scale of the direction finder with the azimuth indicat+ ing scale at. thecentral. point. For this purpose a control'circuit is providedwwhereby' the. direction finder azimuth scale may'be locked. at: a-prea determined reference point and theremote azimuth indicating scale may thenbe moved to: a corresponding point. This arrangement. for orienting the remote azimuth indicating scale. utilizes an improved receiving apparatus. wherein. the control circuit operates an electromagnetto stop the scale at a predetermined referencepoint. In response. to the stopping. of the remote azie muth: indicating scale another electromagnet is.

arranged to be energized to disconnect. the scale. from a motor normally arranged to' drive the scale.

Other and. further objects of the present invention will become more readily apparent by reference to the following description taken in conform of direction finding apparatus, as for examplc a loop antenna, the position of which maybe changed by rotation of a hand wheel til which 50/turns a shaft H which may support the loop antenna. The shaft H is connected through a friction clutch 2 to a gear l3 and an azimuth scale M. The azimuth scale- M cooperates with an'indicatingpoint E5 to show the azimuth of the loop antenna. The azimuth scale I4 is provided which is arranged to be engaged by a detent lever" |1 normally biased away from the azimuth dial l4. The gear l3 drives a gear i6 which is provided with two studs i9 and 2| spaced along a diameter of the gear. These studs I9 and 2| engage levers 22 and 23 which are freely rotatable upon a shaft 24. The ends of the levers 22 and 23 engage the ends of levers 25 and 26, which levers are rigidly secured to the shaft 24. A coil spring 21 interconnects the levers 22 and 25. Another spring 28, operating in the opposite direction with respect to the spring 21, interconnects the levers 23 and 26. This arrangement of levers and springs constitutes an energy storage device so that a gear 29 affixed to the shaft 24 may be rotated through an angular displacement corresponding to an angular displacement of the 4 plurality of field coils 49, 5| and 52 arranged to be energized from the conductors or transmission channels 44 to 46, respectively. These field coils 49, 5| and 52 are mounted on magnetic core or pole structures 53, 54 and 55, respectively, for cooperation with a plurality of armatures 56, 51 and 58. The various armatures 56 to 58 are supported at equal angular displacements on. a shaft 59. The remaining terminals of the field coils 49, 5| and 52 are each connected to the conductor 41 so as to be included in the completeelectric circuit with the impulse transmitting device 35. The impulse responsive motor 48 has its field coils energized in succession in accordance with the completion of circuits by the impulse transmitting device 35. If, for example, the switch 31 were the only switch to be closed the field coil gear l8. If it is assumed that the gear [8 rotates in a clockwise direction the stud 2| will move the lever 23 away from the lever 26, thereby to tension the spring 28 so'that it will cause the lever 26 to follow the movement of the lever 23. The lever 26, however, cannot move in excess of a predetermined rate because of the action of the governor 42 which controls the movement of the gear 29 through gears 4|, 32 and 38. When the shaft 24 and the gear 29 have moved through an angular displacement equal to the angular displacement of the gear IS the lever 26 will again engage the lever 23 whereupon further movement will cease. v

If it is now assumed that the gear l8 moves in a counterclockwise direction the stud l9 will move the lever 22 so as to tension the spring 21. The tension of the spring 21 will cause the lever 25 to follow the movement of the lever 22. If the movement of the lever 22 is at a rate greater than the .rate'at which the shaft 24 may rotate there will be a time delay, but eventually the lever 25 will again reach the lever 22 whereupon rotation of the shaft 24 ceases. Thus it is apparent that there has been provided a follow-up mechanism whereby the gear 29 will be moved through an angular. displacement equal to the angular displacement of the gear l8 but this movement will not exceed a predetermined rate of speed. The

gear 29 drives another gear 36 mounted on a shaft 3| which supports a gear 32. The gear 32 engages a gear 33 mounted on ashaft 34, which at one end is provided with an impulse transmitting device 35. The impulse transmitting device comprises a cam member 36 arranged to actuate a plurality of switches 31, 38 and 39 arranged at equal angular distances about the shaft 34. In order to control or limit the maximum speed at which the shaft 34 may be rotated the gear 32 is arranged to engage a gear 4| which drives a overnor 42.

The follow-up mechanism per se, schematically shown in Fig. 1, may be of the type shown, described and claimed in my copending application for Remote control systems, Serial No. 501,957, filed September 11, 1943.

The transmitting device 35 is connected in a multi-channel circuit which extends to the remote azimuth indicating station. This circuit includes a source of potential, such as a battery 43. The switches 31, 38 and 39 are each connected by suitable transmission channels, such as conductors 44, 45 and 46 to the remote azimuth indicating station. The return circuit to the source of potential' 43 includes a conductor 41. At the remote azimuth indicating station there is provided an impulse-controlled motor 48 which comprises a 49 would be the only one energized so as to cause its armature 56 to be in alignment with the pole structure 53. When two switches, such as 31 and 39, are closed at the same time, field coils 49 and 52 are both energized and for that period of time the armatures 56 and 58 will each tend to move into alignment with the respective polestructures, but because of the angular displacement therebetween neither one is in alignment with its pole structure. If it is assumed that the cam 36 of the impulse transmitter 35 is moving in a clockwise direction, it becomes apparent that shortly thereafter the switch contacts 31 will be opened, whereupon'the field coil 52 will be the only one energized so that its armature 58 will be aligned with its pole structure 55. As the cam 36 continues to rotate the switch 38 will be closed to energize the field coil 5| and thereby tend to bring into alignment with its pole structure 54 its armature 51. The movement of the various armatures produces a movement of" the shaft59= in a direction corresponding to the direction of" The shaft movement of the cam structure 36. 59 is connected to a gear 6| which meshes with a gear 62 mounted upon a sleeve 63.

The sleeve 63 has secured thereto a clutch plate 64 which is arranged to cooperate with a clutch plate 65 mounted upona shaft 66. The clutch plate 64 is spring biased by a'spring 61 toward the clutch plate 65 so as normally to provide a solid driving connection between the sleeve 63 and the shaft 66. The shaft 66 through a gear 68 drives a gear 69 which is secured to the remote azimuth indicating scale 1|. The gear 69 and the indicating scale 1| are afiixed to a circular member 12 having at a predetermined point on gages the notch 13 of the circular member 12;

a spacing link I01 is arranged to move a switch plate to close a pair of switch contacts 19. These switch contacts 19 control the energization of a relay 8| which is arranged to attract its armature 82 to move the lever 98 which engages the spring 61' so as to free the clutch plate 64 from engagement with its cooperating clutch plate 65,

thereby to render ineffective the motor 48. The

relays 11 and 8| are connected in a control circuit which includes the conductor 41, the battery I 43, a switch 83 located at the azimuth observa tion station, and a return conductor 84.

When the direction finder apparatus is set up '5 for use the first steps taken are those to provide a coordination between the azimuth observation scale l4 and the azimuth indicating scale 1|. The operator pushes against the detent H and turns the hand wheel until the detent ll drops into the notch it of theazimuth observation scale 14, whereupon 0 or 360 will register with the indicating pointer I5. While retaining the azimuth scale [4 in this position the wheel i0 is rotated, since the friction of the clutch I2 is such that this is permissible, until a. compass 2% indicates that the loop antenna or direction finding apparatus is aligned with magnetic north. 'I'hereupon the detent l'l is released and the switch 83 is closed so as to energize at the remote azimuth indicating station the magnet ii. The whee1 I8 is then rotated so as to bring about one complete revolution of the azimuth observation scale l4. Rotation of the wheel it produces rotation of the gears 13 and I8. Dependent upon the direction of rotation of the gear l8 one of the two lever-s 22 or 23 will be actuated so as to bring up or tension its associated spring 21 or 2B. The tension on the spring thus produces rotation of the shaft 24 at a rate of speed determined by the governor 42 which, by a gear 4!, is connected to the gear 32. The levers 22 and 23 together with other associated parts including the spring members 21 and 28 constitute a followup mechanism in which mechanical energy is stored so that the shaft 24 is moved through an angular displacement corresponding to that of the gear 18. Due to the step-up gear arrangement between the shaft 1 I and the shaft 34 which is connected to the impulse transmitter 35, a small angular displacement of the shaft H produces a number of revolution of the shaft 34, whereby a plurality of impulses are transmitted over each of the channels 44, 45 and 45, the impulses of each series of impulses being displaced in time relative to the impulses in the other series due to the angular displacement of the switch contacts 31, 38 and 39 about the shaft 34. The impulse device 35 therefore transmits sufficient impulses to cause the impulse receiving motor 48 to produce rotation of the member 12, so that the detent 75 will engage the notch 13. When this occurs the magnet 8! is energized so as to release the clutch mechanism interconnecting the sleeve 63 and the shaft 6%, thereby to render ineifective further action of the motor 48. The operator then continues to turn the wheel H] until the 0 or 360 point is again in alignment with the indicating pointer l5, whereupon the switch 83 is released. Thus the coordination of the reference points on the observation station and the remote indicating station is complete.

In Fig. 2 there is shown a perspective view of a cabinet 85 which houses the remote azimuth indicating apparatus. This cabinet 85 comprises a boxlike structure 36 having a front cover 81 which is provided with an opening 88 through which is visible the dial scale 68. Figs. 3, 4 and show that all of the apparatus contained in the cabinet 85 is supported from the front panel 81. The front panel 81 is provided with a plurality of mounting posts 89 which are secured in position by suitable screws 9! visible from the front of the panel 81. A mounting panel 92 is mounted parallel to the front panel 8'! and some distance therefrom by a plurality of studs 93. The studs 93 are supported from the front panel by a plurality of screws 94 and at their opposite extremities a plurality of screws 95 hold in position the mounting panel 92. The

motor 43 :is provided with a. pair of end plates 9.0 and :96 which, together with mounting stud members :91 secured to the mounting panel 92 retain in proper alignment position the motor pole structures .53, 54 and and the motor shaft 59 which supports the ,armatures 56 to Fill. The motor shaft 5.9 has a gear 6! shown in Fig. 5 which meshes with an anti-backlash .or split gear 62 arranged to drive the clutch plate 64 which is arranged for cooperative relation with the clutch plate 65. If desired a clutch disk may be interposed between the two clutch. plates .andBT: tovprovide the required degree of friction. The clutch plat 64 is biased toward the clutch plate .65 and the clutch disk 66 by a spring iii which bears against a lever 98 pivotally sup ported at at from a supporting bracket vllll suitably secured to the mounting panel 92.. The spring E'i is supported by a bracket I02 suitably secured to the mounting panel 92. At an. intermediate point thereon the lever '98 is provided with the armature 8.2 which cooperates with the relay 3!. The relay 8! is attached to a bracket 194 also suitably secured to the mounting panel 82. The gear 38 which is attached to the shaft tr engages another split anti-backlash gear 69 which is mounted for rotation with the circular member i2 and the dial indicating member H. The circular member F2 is provided with a notch i3 arranged for cooperation with a detent 15 mounted on the outer extremity of an .arm "l6 pivotally mounted upon a pin I85 suitably secured to the mounting panel 92. The lever arm H5 is arranged to be actuated by a linkage which includes a member I securely fastened to the arm 16, a pivoted spacing link! 01 which interconnects the member !96 with a member I08 which is secured to the armature I09 of the relay H. The armature I99 of the relay 1! is pivoted at Hi and is provided with a rearwardly extending arm H2 positioned between two positionin springs H3 and [M which serve to hold the armature H89 in a position so that the detent T5 at the end of the arm 16 normally does not engage the outer periphery of the circular member E2. The outer extremity of the arm H2 is also arranged to engage an insulating member H5 so as to close a pair of contacts 19. The relay l! is supported from the front panel 81 by a suitable bracket H6. The front panel 81 also supports a bracket H8 in which there is mounted a plug connector H9 which, as may be seen from Fig. 2, is arranged to extend to the exterior of the cabinet 85. The plug connector receives the terminal at the end of a cable which includes the conductors 44 to 41 and 84.

From a description of the mode of operation of the telemetrio circuit it will be remembered that when the control circuit was energized by the closure of the switch 83 the relay 1! was energized, thereby tending to pull down its armature I09 and its associated lever 16 so that the detent 15 is in engagement with the periphery of the circular member 12, so that when the notch 13 comes into engagement with the detent 15 the member 12 will be locked in this position. When the arm 16 thus moves an additional distance from that shown in Fig. 3 the armature Hi9 will be moved so its rearwardly extending arm H2 will operate to clos the switch contacts 19, thereby to close the energizing circuit for the relay 8!. The relay 8!, as is apparent from Fig. 5, attracts its armature 82 thereby to pivot the lever 98 rearwardly against the action of the spring 61. Therefore the spring 61 no longer urges the clutch plate 64 into engagement with the clutch plate 65 and the clutch disk 60, so that subsequent rotation of the motor 48 may occur without any strain upon any of the gears. This clutch arrangement also provides for an accurate stopping of the indicating dial H without subsequently introducing an error which might occur in other arrangements due to a strain being placed upon the split. gears 69 and 62. 'When the operator at the azimuth observation station has returned the azimuth indicator to the switch 83 will be released so that both magnets 11 and BI are deenergized. Thereafter any subsequent movement of the azimuth dial at the observation station will produce rotation of the impulse transmitter 35 to bring about a corresponding movement of angular displacement of the azimuth indicating dial H at the remote azimuth indicating station.

While for the purpose of disclosing the present invention a particular circuit arrangement and a particular receiving apparatus has been shown and described, it of course is to be understood that modifications may be made in the circuit arrangements and in the instrumentalities employed without departing from the spirit and 8 ing station, a transmission'channel interconnecting said stations, an angular displaceable indicator at each of said stations, an indexing point on said indicators, means at said transmitting station controllable responsive to angular displacement of said indicator thereat for transmitting a series of impulses over said transmission channel to said receiving station, means at said receiving station operable responsive to said series of impulses for angularly displacing the said indicator thereat an amount corresponding to the angular displacement of said transmitting station indicator, a control channel interconnecting said stations for placing said indicators in alignment, means at said transmitting station for at times energizing said control channel while said transmitting station indicator is angularly displaced a predetermined amount to control said angular displacement of said receiving station indicator over said transmission channel, and means at said receiving station controlled over said energized control channel for terminating angular displacement of said receiving station indicator at said indexing point thereby to align the said indexing points of said transmitting and receiving station indicators when the said predetermined angular displacement of said transmitting station indicator has been terminated and said control channelhas been ,deenergized.

EDWARD s. PETERSON. 

